I forgot to post this to the rest of the group. Paul ----- Original Message ----- From: "Paul Brannon" <pb@mvseasea.com> To: "Mike Maurice" <mikem@yachtsdelivered.com> Sent: Saturday, April 08, 2006 10:25 PM Subject: Re: T&T: VHF problems > The problem exists with two different brands of radios. I tried the new > ICOM 504s today and the problem exists there as well. Someone mentioned > the spacing of the antennas. The antennas are about 5 feet apart and have > a vertical separation as well since the 9db is 20 ft high and the 6db is 8 > ft. The antennas are where they were before I replaced the radios. My > thought is that maybe the newer radios are more sensitive and I may need > to move one antenna. To do this I will need to splice the cable and move > it to the other side of the flybridge. My other thought is that the two > identical radios somehow receive signals in a different way than would be > the case with two different brands of radio. Is there anything unique to > the manufacturing that would cause this as it did not happen when I > changed out one of the radios to a different radio? > > I appreciate the responses to this. > > By the way, what is the minimum spacing for two VHF antennas? > > Thanks, > > Paul > ----- Original Message ----- > From: "Mike Maurice" <mikem@yachtsdelivered.com> > To: <trawlers-and-trawlering@lists.samurai.com> > Sent: Saturday, April 08, 2006 7:35 PM > Subject: Re: T&T: VHF problems > > >> "Paul Brannon" <pb@mvseasea.com> >> At 06:07 PM 4/8/2006 -0400, you wrote: >>>receives the broadcast and will create feedback on the bridge. It also >>>seems >>>that I have a very weak transmitting signal at times but no problem at >>>other >>>the problem does not present. The problem exists regardless of which >>>radio is >>>tuned to 9 or 16. They are on separate antennas; one a 9db and the other >>>6db. >> >> >> I would estimate that you have 2 problems. >> 1. Some transmitting problem that results in a weak output. >> 2. Radios with poor selectivity on receive, that allows channel 9 to >> bleed over onto another channel, such as 16.. >> >> If #2 is correct, the only solution is radios with better >> selectivity. If that is not feasible, you might get by if the >> antennas can be moved further apart. Or, if you can install a blanker >> to disconnect the antenna of the receiving radio whenever the other >> unit is transmitting. >> >> Poor selectivity on receive is generally associated with inexpensive >> receivers. By the way this is a common problem. >> >> >> Mike >> >> Capt. Mike Maurice >> Tualatin(Portland), Oregon >> _______________________________________________ >> http://lists.samurai.com/mailman/listinfo/trawlers-and-trawlering >> >> To unsubscribe send email to >> trawlers-and-trawlering-request@lists.samurai.com with the word >> UNSUBSCRIBE and nothing else in the subject or body of the message. >> >> Trawlers & Trawlering and T&T are trademarks of Water World >> Productions. Unauthorized use is prohibited.

Paul, Are the bases of the antennas separated by 20 feet? Ron Rogers

You probably have answered this for your self - It happens when the two radios are the same make. I suspect the radios being too close is the problem - The IF (intermediate frequencies) in the radios are the same and that is what is being picked up. Another "possibility" is common grounds. John Gallagher >I forgot to post this to the rest of the group. > >Paul >----- Original Message ----- >From: "Paul Brannon" <pb@mvseasea.com> >To: "Mike Maurice" <mikem@yachtsdelivered.com> >Sent: Saturday, April 08, 2006 10:25 PM >Subject: Re: T&T: VHF problems > > >> The problem exists with two different brands of radios. I tried the new >> ICOM 504s today and the problem exists there as well. Someone mentioned >> the spacing of the antennas. The antennas are about 5 feet apart and have >> a vertical separation as well since the 9db is 20 ft high and the 6db is 8 >> ft. The antennas are where they were before I replaced the radios. My >> thought is that maybe the newer radios are more sensitive and I may need >> to move one antenna. To do this I will need to splice the cable and move >> it to the other side of the flybridge. My other thought is that the two >> identical radios somehow receive signals in a different way than would be >> the case with two different brands of radio. Is there anything unique to >> the manufacturing that would cause this as it did not happen when I >> changed out one of the radios to a different radio? >> >> I appreciate the responses to this. >> >> By the way, what is the minimum spacing for two VHF antennas? >> >> Thanks, >> >> Paul >> ----- Original Message ----- >> From: "Mike Maurice" <mikem@yachtsdelivered.com> >> To: <trawlers-and-trawlering@lists.samurai.com> >> Sent: Saturday, April 08, 2006 7:35 PM >> Subject: Re: T&T: VHF problems >> >> >>> "Paul Brannon" <pb@mvseasea.com> >>> At 06:07 PM 4/8/2006 -0400, you wrote: >>>>receives the broadcast and will create feedback on the bridge. It also >>>>seems >>>>that I have a very weak transmitting signal at times but no problem at >>>>other >>>>the problem does not present. The problem exists regardless of which >>>>radio is >>>>tuned to 9 or 16. They are on separate antennas; one a 9db and the other >>>>6db. >>> >>> >>> I would estimate that you have 2 problems. >>> 1. Some transmitting problem that results in a weak output. >>> 2. Radios with poor selectivity on receive, that allows channel 9 to >>> bleed over onto another channel, such as 16.. >>> >>> If #2 is correct, the only solution is radios with better >>> selectivity. If that is not feasible, you might get by if the >>> antennas can be moved further apart. Or, if you can install a blanker >>> to disconnect the antenna of the receiving radio whenever the other >>> unit is transmitting. >>> >>> Poor selectivity on receive is generally associated with inexpensive >>> receivers. By the way this is a common problem. >>> >>> >>> Mike >>> >>> Capt. Mike Maurice >>> Tualatin(Portland), Oregon >>> _______________________________________________ >>> http://lists.samurai.com/mailman/listinfo/trawlers-and-trawlering >>> >>> To unsubscribe send email to >>> trawlers-and-trawlering-request@lists.samurai.com with the word >>> UNSUBSCRIBE and nothing else in the subject or body of the message. >>> >>> Trawlers & Trawlering and T&T are trademarks of Water World >>> Productions. Unauthorized use is prohibited. >_______________________________________________ >http://lists.samurai.com/mailman/listinfo/trawlers-and-trawlering > >To unsubscribe send email to >trawlers-and-trawlering-request@lists.samurai.com with the word >UNSUBSCRIBE and nothing else in the subject or body of the message. > >Trawlers & Trawlering and T&T are trademarks of Water World >Productions. Unauthorized use is prohibited.